//! Governance, burns, and bytes moving between clusters.

use smart_byte_core::keys::IndexedSignature;
use smart_byte_core::{Aid, Cargo, Envelope, JouleCost, Said, SigningKey};
use smart_byte_keri_witness::{Controller, KeyEvent, KeyPair, Threshold};
use smart_byte_state::certificate::node_key;
use smart_byte_state::{Approval, Burn, Certificate, Change, Input, Proposal, State};

fn key(label: &str) -> KeyPair {
    KeyPair::from_signing(SigningKey::from_bytes(&Said::hash(label.as_bytes()).0))
}

/// A one-key controller and the signed events of its log so far.
struct Party {
    c: Controller,
    log: Vec<(KeyEvent, Vec<IndexedSignature>)>,
}

impl Party {
    fn new(label: &str) -> Self {
        let (c, icp) = Controller::incept(
            vec![key(&format!("{label}-0"))],
            vec![key(&format!("{label}-1"))],
            Threshold(1),
            Threshold(1),
            vec![],
            Threshold(0),
        )
        .unwrap();
        let event = KeyEvent::Inception(icp);
        let sigs = sigs(&c, &event);
        Party {
            c,
            log: vec![(event, sigs)],
        }
    }
    fn aid(&self) -> Aid {
        self.c.aid
    }
    fn incept(&self) -> Vec<u8> {
        Input::key_event(&self.log[0].0, &self.log[0].1)
    }
    fn approve(&self, proposal: &Proposal) -> Approval {
        Approval {
            approver: self.aid(),
            signature: self
                .c
                .signer()
                .sign(&smart_byte_core::wire::to_vec(proposal).unwrap()),
        }
    }
}

fn sigs(c: &Controller, event: &KeyEvent) -> Vec<IndexedSignature> {
    c.sign_event(event)
        .unwrap()
        .into_iter()
        .map(|(index, signature)| IndexedSignature {
            index: u64::from(index),
            signature,
        })
        .collect()
}

fn classes(report: &smart_byte_state::FrameReport) -> Vec<Result<(), &'static str>> {
    report
        .results
        .iter()
        .map(|r| r.outcome.as_ref().map(|_| ()).map_err(|e| e.class()))
        .collect()
}

fn sorted(mut v: Vec<Result<(), &'static str>>) -> Vec<Result<(), &'static str>> {
    v.sort();
    v
}

const USD: u64 = 1;

fn cluster(label: &str) -> Said {
    Said::hash(label.as_bytes())
}

#[test]
fn an_issuer_is_added_by_the_others_and_only_after_the_delay() {
    let (a, b, c, new) = (
        Party::new("a"),
        Party::new("b"),
        Party::new("c"),
        Party::new("new"),
    );
    let id = cluster("one");
    let mut state = State::genesis(id, [(a.aid(), USD), (b.aid(), USD), (c.aid(), USD)], [], 2);
    state.apply_frame(&[a.incept(), b.incept(), c.incept(), new.incept()]);

    let proposal = Proposal {
        cluster: id,
        sequence: 0,
        change: Change::AddIssuer {
            cargo_type: USD,
            issuer: new.aid(),
        },
    };
    // Three issuers: the quorum is floor(2·3/3)+1 = 3.
    let two = Input::governance(&proposal, &[a.approve(&proposal), b.approve(&proposal)]);
    let three = Input::governance(
        &proposal,
        &[
            a.approve(&proposal),
            b.approve(&proposal),
            c.approve(&proposal),
        ],
    );
    assert_eq!(
        classes(&state.apply_frame(&[two])),
        vec![Err("below_quorum")]
    );
    assert_eq!(classes(&state.apply_frame(&[three.clone()])), vec![Ok(())]);
    assert_eq!(state.governance.pending.len(), 1);
    assert_eq!(state.governance.pending[0].effective, 2 + 1 + 2);

    // The same proposal again: its sequence number is spent.
    assert_eq!(
        classes(&state.apply_frame(&[three])),
        vec![Err("stale_sequence")]
    );

    let mint = |label: &str, frame_note: &str| {
        let e = Envelope::issue(
            &new.c.signer(),
            a.aid(),
            [frame_note.len() as u8; 16],
            Cargo::usd_micros(1),
            JouleCost::default(),
        );
        let _ = label;
        Input::mint(&e.provenance)
    };
    // Frame 4: not yet in force.
    assert_eq!(state.frame, 4);
    assert_eq!(
        classes(&state.apply_frame(&[mint("early", "x")])),
        vec![Err("issuer_not_registered")]
    );
    // Frame 5: in force from its start.
    assert_eq!(
        classes(&state.apply_frame(&[mint("in force", "xy")])),
        vec![Ok(())]
    );
    assert!(state.authorizes(&new.aid(), USD) && state.governance.pending.is_empty());
}

#[test]
fn governance_is_checked_before_it_is_counted() {
    let (a, b, outsider) = (Party::new("a"), Party::new("b"), Party::new("outsider"));
    let id = cluster("one");
    let mut state = State::genesis(id, [(a.aid(), USD), (b.aid(), USD)], [], 0);
    state.apply_frame(&[a.incept(), b.incept(), outsider.incept()]);
    let p = |change: Change, sequence: u64, cluster: Said| Proposal {
        cluster,
        sequence,
        change,
    };
    let add = |issuer: Aid| Change::AddIssuer {
        cargo_type: USD,
        issuer,
    };
    let remove = |issuer: Aid| Change::RemoveIssuer {
        cargo_type: USD,
        issuer,
    };

    let elsewhere = p(add(outsider.aid()), 0, cluster("two"));
    let stale = p(add(outsider.aid()), 7, id);
    let registered = p(add(a.aid()), 0, id);
    let unregistered = p(remove(outsider.aid()), 0, id);
    let by_outsider = p(add(outsider.aid()), 0, id);
    let twice = p(add(outsider.aid()), 0, id);
    let report = state.apply_frame(&[
        Input::governance(&elsewhere, &[a.approve(&elsewhere), b.approve(&elsewhere)]),
        Input::governance(&stale, &[a.approve(&stale), b.approve(&stale)]),
        Input::governance(
            &registered,
            &[a.approve(&registered), b.approve(&registered)],
        ),
        Input::governance(
            &unregistered,
            &[a.approve(&unregistered), b.approve(&unregistered)],
        ),
        Input::governance(
            &by_outsider,
            &[a.approve(&by_outsider), outsider.approve(&by_outsider)],
        ),
        Input::governance(&twice, &[a.approve(&twice), a.approve(&twice)]),
    ]);
    assert_eq!(
        sorted(classes(&report)),
        sorted(vec![
            Err("wrong_cluster"),
            Err("stale_sequence"),
            Err("already_registered"),
            Err("not_registered"),
            Err("not_an_elector"),
            Err("duplicate_approver"),
        ])
    );
    assert_eq!(state.governance.sequence, 0);
}

#[test]
fn an_issuer_cannot_block_its_own_removal() {
    let (a, b, c) = (Party::new("a"), Party::new("b"), Party::new("c"));
    let id = cluster("one");
    let mut state = State::genesis(id, [(a.aid(), USD), (b.aid(), USD), (c.aid(), USD)], [], 0);
    state.apply_frame(&[a.incept(), b.incept(), c.incept()]);
    let proposal = Proposal {
        cluster: id,
        sequence: 0,
        change: Change::RemoveIssuer {
            cargo_type: USD,
            issuer: c.aid(),
        },
    };
    // The electorate is the other two; both approve. The target's vote is
    // not counted, and not needed.
    let with_target = Input::governance(&proposal, &[a.approve(&proposal), c.approve(&proposal)]);
    assert_eq!(
        classes(&state.apply_frame(&[with_target])),
        vec![Err("not_an_elector")]
    );
    let others = Input::governance(&proposal, &[a.approve(&proposal), b.approve(&proposal)]);
    assert_eq!(classes(&state.apply_frame(&[others])), vec![Ok(())]);
    state.apply_frame(&[]);
    assert!(!state.authorizes(&c.aid(), USD));
}

#[test]
fn redemption_is_a_return_to_the_issuer_and_a_burn() {
    let (issuer, alice) = (Party::new("issuer"), Party::new("alice"));
    let mut state = State::genesis(cluster("one"), [(issuer.aid(), USD)], [], 0);
    let byte = Envelope::issue(
        &issuer.c.signer(),
        alice.aid(),
        [1; 16],
        Cargo::usd_micros(5),
        JouleCost::default(),
    );
    let mint = Input::mint(&byte.provenance);
    state.apply_frame(&[issuer.incept(), alice.incept(), mint.clone()]);
    let id = byte.identity();

    // Alice returns it; the issuer burns it in the same frame: burns apply
    // after transfers.
    let back = byte.transfer(&alice.c.signer(), issuer.aid(), 1);
    let t = back.ownership_chain.last().unwrap();
    let burn = Burn::sign(&issuer.c.signer(), id, back.history_hash(), 1);
    let by_alice = Burn::sign(&alice.c.signer(), id, back.history_hash(), 1);
    let report = state.apply_frame(&[
        Input::burn(&burn),
        Input::burn(&by_alice),
        Input::transfer(&id, t),
    ]);
    assert_eq!(
        sorted(classes(&report)),
        sorted(vec![Ok(()), Ok(()), Err("not_current_owner")])
    );
    assert!(state.bytes.is_empty());
    assert_eq!(state.retired[&id].owner, issuer.aid());

    // Burned for good: no transfer, no re-mint.
    let after = Burn::sign(&issuer.c.signer(), id, back.history_hash(), 2);
    assert_eq!(
        sorted(classes(&state.apply_frame(&[Input::burn(&after), mint]))),
        vec![Err("byte_retired"), Err("duplicate_byte")]
    );
}

/// Two clusters, each with four nodes, peering with each other.
struct Federation {
    a: State,
    b: State,
    a_nodes: Vec<SigningKey>,
    b_nodes: Vec<SigningKey>,
}

fn federation(registry: &[(Aid, u64)]) -> Federation {
    let nodes = |label: &str| {
        (0..4)
            .map(|i| SigningKey::from_bytes(&Said::hash(format!("{label}-node-{i}").as_bytes()).0))
            .collect::<Vec<_>>()
    };
    let (a_nodes, b_nodes) = (nodes("a"), nodes("b"));
    let keys = |n: &[SigningKey]| n.iter().map(node_key).collect::<Vec<_>>();
    Federation {
        a: State::genesis(
            cluster("A"),
            registry.iter().copied(),
            [(cluster("B"), keys(&b_nodes))],
            0,
        ),
        b: State::genesis(
            cluster("B"),
            registry.iter().copied(),
            [(cluster("A"), keys(&a_nodes))],
            0,
        ),
        a_nodes,
        b_nodes,
    }
}

fn certify(
    statement: smart_byte_state::ExportStatement,
    nodes: &[SigningKey],
    signers: &[u64],
) -> Certificate {
    let picked: Vec<(u64, &SigningKey)> =
        signers.iter().map(|i| (*i, &nodes[*i as usize])).collect();
    Certificate::sign(statement, &picked)
}

#[test]
fn a_byte_moves_between_clusters_and_back() {
    let (issuer, alice, bob) = (Party::new("issuer"), Party::new("alice"), Party::new("bob"));
    let mut f = federation(&[(issuer.aid(), USD)]);
    let byte = Envelope::issue(
        &issuer.c.signer(),
        alice.aid(),
        [1; 16],
        Cargo::usd_micros(5),
        JouleCost::default(),
    );
    let id = byte.identity();
    f.a.apply_frame(&[
        issuer.incept(),
        alice.incept(),
        Input::mint(&byte.provenance),
    ]);
    f.b.apply_frame(&[bob.incept()]);

    // Alice sends it to Bob, in cluster B.
    let out = byte.export(&alice.c.signer(), bob.aid(), 1, cluster("B"));
    let report =
        f.a.apply_frame(&[Input::transfer(&id, out.ownership_chain.last().unwrap())]);
    assert_eq!(classes(&report), vec![Ok(())]);
    assert!(f.a.bytes.is_empty() && f.a.exported.contains_key(&id));
    let statement = report.exports[0].clone();
    // A transfer of a byte that has left is refused.
    let stale = byte.transfer(&alice.c.signer(), issuer.aid(), 2);
    assert_eq!(
        classes(&f.a.apply_frame(&[Input::transfer(&id, stale.ownership_chain.last().unwrap())])),
        vec![Err("byte_exported")]
    );

    let logs = vec![issuer.log.clone(), alice.log.clone()];
    let import = |cert: &Certificate, logs: &[Vec<(KeyEvent, Vec<IndexedSignature>)>]| {
        Input::import(cert, &out, logs)
    };
    let three = certify(statement.clone(), &f.a_nodes, &[0, 1, 2]);
    let two = certify(statement.clone(), &f.a_nodes, &[0, 2]);
    let missing_log = import(&three, &logs[..1]);
    let report = f.b.apply_frame(&[import(&two, &logs), missing_log]);
    assert_eq!(
        sorted(classes(&report)),
        vec![Err("below_threshold"), Err("unknown_key_state")]
    );
    // With three of A's four nodes and every log the history needs: applied.
    assert_eq!(
        classes(&f.b.apply_frame(&[import(&three, &logs)])),
        vec![Ok(())]
    );
    assert_eq!(f.b.bytes[&id].owner, bob.aid());
    assert_eq!(f.b.bytes[&id].history_hash, out.history_hash());
    // Once.
    assert_eq!(
        classes(&f.b.apply_frame(&[import(&three, &logs)])),
        vec![Err("duplicate_import")]
    );

    // Bob sends it back to Alice in A; A takes it back over its own export.
    let home = out.export(&bob.c.signer(), alice.aid(), f.b.frame, cluster("A"));
    let report =
        f.b.apply_frame(&[Input::transfer(&id, home.ownership_chain.last().unwrap())]);
    assert_eq!(classes(&report), vec![Ok(())]);
    let cert = certify(report.exports[0].clone(), &f.b_nodes, &[1, 2, 3]);
    let logs = vec![issuer.log.clone(), alice.log.clone(), bob.log.clone()];
    assert_eq!(
        classes(&f.a.apply_frame(&[Input::import(&cert, &home, &logs)])),
        vec![Ok(())]
    );
    assert!(f.a.bytes.contains_key(&id) && !f.a.exported.contains_key(&id));
    // A's first certificate, replayed in A, is not for A.
    assert_eq!(
        classes(&f.a.apply_frame(&[import(&three, &[issuer.log.clone(), alice.log.clone()])])),
        vec![Err("wrong_cluster")]
    );
}

#[test]
fn an_import_must_be_the_byte_certified() {
    let (issuer, alice, bob) = (Party::new("issuer"), Party::new("alice"), Party::new("bob"));
    let mut f = federation(&[(issuer.aid(), USD)]);
    let byte = Envelope::issue(
        &issuer.c.signer(),
        alice.aid(),
        [1; 16],
        Cargo::usd_micros(5),
        JouleCost::default(),
    );
    let id = byte.identity();
    f.a.apply_frame(&[
        issuer.incept(),
        alice.incept(),
        Input::mint(&byte.provenance),
    ]);
    let out = byte.export(&alice.c.signer(), bob.aid(), 1, cluster("B"));
    let report =
        f.a.apply_frame(&[Input::transfer(&id, out.ownership_chain.last().unwrap())]);
    let cert = certify(report.exports[0].clone(), &f.a_nodes, &[0, 1, 2]);
    let logs = vec![issuer.log.clone(), alice.log.clone()];
    // The envelope before the export: not the history A certified.
    let report = f.b.apply_frame(&[Input::import(&cert, &byte, &logs)]);
    assert_eq!(classes(&report), vec![Err("certificate_mismatch")]);
    // A certificate from a cluster B does not peer with.
    let mut stranger = f.b.clone();
    stranger.peers.clear();
    assert_eq!(
        classes(&stranger.apply_frame(&[Input::import(&cert, &out, &logs)])),
        vec![Err("unknown_cluster")]
    );
    // An export to a cluster A does not peer with is refused in A.
    let lost = byte.export(&alice.c.signer(), bob.aid(), 2, cluster("nowhere"));
    let mut a = f.a.clone();
    a.exported.clear();
    a.bytes.insert(
        id,
        smart_byte_state::ByteRecord {
            issuer: issuer.aid(),
            cargo: Cargo::usd_micros(5),
            minted: 0,
            owner: alice.aid(),
            history_hash: id.0,
        },
    );
    assert_eq!(
        classes(&a.apply_frame(&[Input::transfer(&id, lost.ownership_chain.last().unwrap())])),
        vec![Err("unknown_cluster")]
    );
}

#[test]
fn peers_change_by_governance() {
    let (a, b) = (Party::new("a"), Party::new("b"));
    let id = cluster("one");
    let mut state = State::genesis(id, [(a.aid(), USD), (b.aid(), 2)], [], 0);
    state.apply_frame(&[a.incept(), b.incept()]);
    let node = SigningKey::from_bytes(&[9; 32]);
    let proposal = Proposal {
        cluster: id,
        sequence: 0,
        change: Change::SetPeer {
            peer: cluster("two"),
            keys: vec![node_key(&node)],
        },
    };
    // Peer changes are every issuer's business: both must approve.
    let one = Input::governance(&proposal, &[a.approve(&proposal)]);
    let both = Input::governance(&proposal, &[a.approve(&proposal), b.approve(&proposal)]);
    assert_eq!(
        classes(&state.apply_frame(&[one])),
        vec![Err("below_quorum")]
    );
    assert_eq!(classes(&state.apply_frame(&[both])), vec![Ok(())]);
    state.apply_frame(&[]);
    assert!(state.peers.contains_key(&cluster("two")));
    // A peer's keys must be keys.
    let bad = Proposal {
        cluster: id,
        sequence: 1,
        change: Change::SetPeer {
            peer: cluster("three"),
            keys: vec![smart_byte_core::PrefixedKey(vec![1, 2, 3])],
        },
    };
    assert_eq!(
        classes(
            &state.apply_frame(&[Input::governance(&bad, &[a.approve(&bad), b.approve(&bad)])])
        ),
        vec![Err("malformed_verifying_key")]
    );
}